What Are Rack Power Distribution Units (PDUs)?

To define PDU, we simply need to know what PDU stands for. A PDU, or Power Distribution Unit, is a device used in data centers to control and distribute electric power. The most basic form of a PDU is a large power strip without surge protection. This is designed to provide standard electrical outlets for use within a variety of settings that don't require monitoring or remote access capabilities.

For larger projects, a floor-mounted PDU sometimes referred to as the Main Distribution Unit, provides a crucial management bridge that connects the building's primary power source and a variety of equipment racks within a data center or remote location. These units can handle considerably larger amounts of energy as well as the ability to support the load required by multiple racks of gear.

A rack-mounted PDU mounts directly into the equipment rack so it can monitor and control the power supply to specific servers, switches, and other data center devices and assist in balancing power loads. These PDUs can be described by several different names including 'Smart' or Intelligent PDUs.

PDU Definition

The acronym "PDU" stands for Power Distribution Unit. Basic PDUs are, essentially, industrial-grade power strips used (in most cases) to power servers and telecommunications equipment.

A basic PDU supplies power to server racks without advanced functionality. These are a low-cost server rack power distribution option.

You'll generally have too many devices at a site to plug them all directly into your power supply. You need PDUs to distribute your site's power to each device. This is possible because a PDU turns one (or a few) power inputs into many (usually about eight) power outputs.

In other words, a power PDU is responsible for distributing reliable network power to your multiple devices. It can't generate power (so it's not a secondary power source), but it delivers AC or DC power from an uninterruptible power supply (UPS), a generator, or utility power to your remote equipment.

A power strip is a great example as a basic PDU, meaning it powers multiple devices using the current of a single power source, such as a wall outlet. Besides power distribution, modern PDU units can help you with equipment, environmental, and power monitoring.

Common Types of PDU

Switched PDUs and metered PDU unis are two of the most common types of power distribution units.

Metered PDUs provide network-grade power distribution. Switched PDUs also provide network-grade power distribution, but also remote monitoring and outlet control.

Switched PDUs make it possible for you to remotely monitor and manage your outlets and other devices.

AC and DC PDU Units

PDUs are available in both AC and DC models to match the power requirements at different kinds of sites. In most cases, an AC PDU will be powered with AC power and will distribute power with an alternating current. DC PDUs will sometimes differ in the sense that they all distribute DC power, but the PDU itself may be powered with AC or DC power, depending on the requirements of your site.

From a field tech's point of view, the units would function identically. DC units are built just like their AC counterparts, except for their output current.

DC power distribution units are designed to provide electric current in the direct current format that many rack-mounted devices use.

Rack PDU Definition

Now let's add another layer to our definition by adding the word "rack."

A basic "rack PDU" is a PDU that is designed to be mounted in an industry-standard equipment rack. These server racks are typically either 19 inches or 23 inches in width. Height can vary from PDU to PDU, but most are just one "rack unit" high. This translates to about 1.75 inches.

A rack-mountable PDU is different from other kinds of PDUs that are designed to be wall-mounted or attached to the side of an equipment rack. These other PDUs conserve valuable physical rack space in cramped equipment racks, but they do increase the distance between the power outputs of the PDU and the power inputs of the devices that will receive electricity.

A rack-mounted power distribution unit usually can manage and distribute large amounts of electricity. They typically allow you to connect them to your current monitoring system and can be accessed remotely.

Benefits of Intelligent PDUs

Intelligent power distribution units are an important part of an integrated monitoring system that protects mission-critical equipment. An efficient unit will allow you to monitor and control the power at your individual outlets, switch power on or off, remotely shut down the power during an emergency power outage, and also allocate power efficiently.

Also, keep in mind that PDUs that were designed to meet your specific needs will be able to provide you with customized features to attend your remote sites' requirements.

In a nutshell, the most important advantages PDUs offer include:

• You'll know you where your energy is going.
  The best PDUs will be able to give you monitoring capabilities as well as power consumption data. This way, your network techs will be able to know where energy is being consumed the most.
• You'll have better control over your power.
  Your technicians will be able to remotely toggle even individual outlets. This makes it possible to turn off non-essential gear when an outage happens and UPS runtime needs to be maximized. Also, you can remotely restart your equipment after an issue to restore normal operations.
• You'll save money on network components.
  The most modern PDUs will allow you to daisy-chain network connectivity, so you'll only need a single port and one IP address for multiple PDUs.
• Up-to-the-minute information about remote equipment.
  Advanced PDUs will have intuitive web interfaces that be accessed by your techs when they need information about remote sites, such as alarms. Not only that, but you'll also get immediate notification about alarms and issues through whichever method you prefer, like email or text messages. This all makes it possible to check the operation of your remote power system in real-time so you can detect and correct problems in a timely manner.

If you would like to know more about our industrial AC or DC PDU line, don't hesitate to reach out to us!

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